1. Technical Field
This invention pertains to wells and a system for controlling flow in a well flow conduit which utilizes a standing valve. Standing valves are frequently installed in well flow conduits to permit formation fluids to flow into the well flow conduit and upward through the conduit and standing valve to the surface. Standing valves protect well formations from contamination, especially low pressure formations, by preventing fluids in the flow conductor from flowing or being pumped down the flow conduit into the formation.
2. Information
Otis Engineering Corporation Products and Services Catalog (OEC 5516) shows, on page 245, a typical ball/cage standing valve, used in a retrievable only standing valve assembly, which has been installed in a foot valve in a well flow conduit.
A standing valve embodiment of a lock mandrel is disclosed in copending application for patent, Ser. No. 449,807, filed 13 Dec., 1989 for EXPENDABLE DEVICES FOR WELL LOCK SYSTEM. This lock mandrel is expendable only as it has a lower locking ring, which prevents retrieval and the upper locking ring is retained in expanded position by a retainer ring releasably positioned on the lock mandrel body.
U.S. Pat. No. 4,352,366 discloses a retrievable standing valve having a ball valve which is rotated to close by upward flow through a choke in the ball member. U.S. Pat. No. 4,352,366 is herein incorporated for reference.